Architects and designers have recognized the need to create spaces that not only meet functional requirements but also prioritize the mental and emotional well-being of occupants. In this context, glazing, with its unique ability to connect indoor and outdoor spaces, has emerged as a powerful tool for supporting this vital goal. By harnessing the transformative potential of natural light and views, architectural glazing enhances the physical aesthetics of a space while having a profound impact on the psychological and emotional experience of those within it. This course explores the significant role of glazing in promoting mental health and well-being and discusses how designers can effectively incorporate this element to nurture and support individuals in their daily lives.
Photo: Matthew Cassity; courtesy of TBA Studio
A classroom in the new Boley Elementary School in West Monroe, Louisiana. A playful color palette is seen throughout the building, creating a stimulating and positive atmosphere, ideal for primary school settings.
THE IMPORTANCE OF DAYLIGHTING AND VIEWS
Daylighting—the practice of incorporating natural light into the design of buildings—has a rich history spanning thousands of years. Throughout different periods and architectural styles, architects have recognized the benefits of daylight in creating comfortable and aesthetically pleasing spaces. Still, there have been times in which designers chose artificial lighting over daylighting in response to increasing electrical technologies, among other reasons.
In more recent decades, daylighting has reemerged as a critical aspect of green building and healthy design, incorporating strategies like solar orientation, shading devices, light redirecting systems, and efficient glazing to maximize natural light while minimizing heat gain and glare. In addition, ongoing research has shown that humans occupying the built environment require natural light, views, and ventilation to maintain their health and well-being—and, in fact, thrive.
In the architecture, engineering, and construction industry, mental health is gaining attention and being prioritized when designing buildings and specifying materials. Glass is a key product that can optimize both mental and physical health—whether at home, school, work, or in medical centers—and larger glass sizes are being used to increase natural daylight and views.
Photo: Benjamin Benschneider; courtesy of Sentech Architectural Systems
Expedia Group’s new Seattle headquarters. The facade features insulating glass units with a (pre-tensioned) cable-supported structural glass wall system.
Glazing and Mental Health
Glazing allows natural light to enter a building, creating a connection to the outdoors and providing views of the surrounding environment. Access to natural light has been linked to improved mood, increased productivity, and better overall mental health. It can enhance the occupants' sense of well-being and create a more pleasant and stimulating environment.
Architectural glazing can be part of biophilic design, which aims to incorporate elements of nature into built environments. Views of nature, such as greenery or water features, can have a calming effect, reducing stress, and improving cognitive function.
Large windows or open glass partitions can promote visual connectivity between spaces and encourage social interaction among occupants. The transparency of architectural glazing can create a sense of openness and spaciousness in interior spaces, which can contribute to a feeling of freedom, reduce feelings of confinement, and alleviate symptoms of claustrophobia or anxiety.
Glazing systems can also help satisfy our need for safety. The right design can provide connectivity to the outside world and, at the same time, provide privacy and security.
Circadian Rhythms
How—exactly—does daylighting affect the body? Let’s start with circadian rhythm. The circadian rhythm is a natural, internal process that regulates the sleep-wake cycle and various other physiological and behavioral processes in living organisms, including humans. It is often referred to as the "body clock" or the “biological clock.” The term “circadian” comes from the Latin words “circa” (meaning “around”) and “diem” (meaning ”day”), reflecting the fact that these rhythms occur on a roughly 24-hour cycle.
In humans, the circadian rhythm is primarily influenced by environmental cues, with the most significant one being the daily light-dark cycle. Specialized cells in the retina of the eye called ganglion cells detect light and send signals to the brain, which is considered the master pacemaker of the circadian system. The SCN, located in the hypothalamus, synchronizes various bodily functions and processes to align with the external light-dark cycle. It regulates the release of hormones, body temperature, metabolism, cognitive functions, and even mood. Melatonin is a key player in the circadian rhythm, as its secretion is regulated by the SCN and helps regulate sleep.
Disruptions to the circadian rhythm, such as irregular sleep patterns, shift work, jet lag, or exposure to artificial light at night, can have adverse effects on human health and well-being. Physical effects of disrupted circadian systems could span everything from cardiovascular disease to cancer. Mental effects can include irritability, depression, negative mood, impaired memory, and anxiety—all of which can compound over time into chronic mental illness. Poor mental health also feeds into poor physical health, and vice versa.
On the other hand, people with aligned circadian rhythms tend to experience the opposite: stable or elevated moods, lower stress, and higher cognitive function, which tends to lead to good coping skills, positive social interactions, motivation and productivity, and a more positive sense of self and the surrounding environment. These types of positive changes also have a compounding effect; they often help prevent chronic illness and lead to decision-making that perpetuates good mental health.
Schools and Mental Health
Research has shown that integrating architectural glazing in educational settings produces a multitude of benefits significantly impacting the health, growth, and performance of building occupants. One of the most notable mental health outcomes is the increase in attendance for both students and teachers. Well-designed glazing that allows ample natural light to flood the classrooms and common areas results in students feeling more energized and engaged and leads to a higher level of enthusiasm for attending school. Teachers also benefit from improved well-being and job satisfaction since natural light positively impacts mood and overall sense of comfort. Students achieve 5-14 percent higher test scores and learn 20-26 percent faster when classrooms have access to daylight and views.
Architectural glazing in educational spaces has also been linked to a marked improvement in student behavior. Studies have consistently shown that students in windowless classrooms exhibit more hostile and disruptive behaviors compared to their counterparts in classrooms with ample natural light. The exposure to natural light and outdoor views through glazing helps create a sense of tranquility and reduces feelings of confinement, resulting in better student behavior and a more conducive learning environment.
Anecdotal evidence from teachers further supports the positive impact of glazing with views of nature. Teachers have reported having access to better windows and natural views helped them and their students stay calm and regroup during times of heightened stress. Additionally, studies have shown that a lack of daylight can disrupt hormone patterns in children, making it more challenging for them to concentrate and collaborate effectively with their peers. These effects can have significant long-term consequences, not only on academic performance and overall growth but on their general mental health.
Photo: Matthew Cassity; courtesy of TBA Studio
The new daylit and colorful interior of Boley Elementary School designed by TBA Studios helped students and teachers get back to learning as soon as possible after a 2019 fire destroyed the previous building.
Healthcare Settings and Mental Health
In the 19th century, Florence Nightingale observed the poor conditions in hospitals and recognized the impact of the physical environment on patient outcomes. She emphasized the importance of natural light in healthcare settings, particularly in hospitals, to improve the well-being and recovery of patients. She urged architects and hospital administrators to design and build hospitals with large windows and open spaces and promoted the use of architectural glazing in hospital wards, corridors, and common areas. Her ideas laid the foundation for evidence-based healthcare design, with daylighting becoming a fundamental aspect of modern hospital architecture.
Architectural design did take a turn away from daylighting when architects—to utilize new technologies and control lighting—began designing with artificial light. But decades of research have reaffirmed Nightingale’s early theory. Roger Ulrich, a prominent researcher, has conducted more than 50 studies that have significantly influenced the design of healthcare facilities, emphasizing the importance of creating healing environments that support patient well-being and recovery. His most famous study, the 1984 "View Through a Window May Influence Recovery from Surgery" revealed that patients who had a view of nature from their hospital room experienced better postoperative outcomes, including shorter hospital stays and reduced need for pain medication.
Ulrich's research suggested that exposure to nature, even through a window, could help reduce stress, promote healing, and enhance overall well-being during the recovery process. It also highlighted for architects the importance of considering, in advance, the design of healthcare environments and incorporating elements such as access to daylight, green spaces, and views of nature.
In a 2001 study, bipolar patients exposed to daylight and a view of nature had hospital stays that were 3.7 days shorter than those without views and daylight. Other research has shown that Alzheimer’s patients show lower agitation levels with higher exposure to daylight. The impact on medical staff has also been shown to be significant. Views and daylighting have shown a reduction in both stress and risk of circadian rhythm disruption. These elements have decreased sick days by up to 6.5 percent, reduced medication dispensing errors, improved alertness, and improved task performance.
Despite this research, only 44 percent of occupants have access to daylight in state-of-the-art U.S. hospitals. Often, only a small percentage of the floor area is within 15 feet of a window. So, while patient rooms may have more access to light and views, staff still are not provided the same access.
The Workplace and Mental Health
Architectural design plays a crucial role in supporting positive mental health in the workplace, and research has consistently shown that well-designed work environments with access to daylighting and views of nature have significant benefits for employees and businesses alike. Studies conducted over the past two decades have demonstrated that workers in daylit office buildings are 18 percent more productive, leading to a 20 percent increase in overall employee performance.
Additionally, employees working in spaces with views of the outdoors experience a boost in mental function and memory by 10-25 percent, along with increased information processing speed compared to colleagues without such views. "People are often unconscious of glancing out a window, notes Lisa Heschong, author and scientific researcher. They will glance out a window for about 50 percent of the time while they are working if they have the opportunity to," she says, and the action results in larger working memory and long-term memory consolidation. "This is supportive of cognitive function." Architects know this, she says. "Great architecture celebrates the view," says Heschong.
The impact of thoughtful architectural design goes beyond productivity gains. Workers exposed to daylighting and nature views report better quality of life scores, increased vitality, and improved sleep efficiency. The presence of natural light and access to views have been linked to a reduction in absenteeism and employee turnover, allowing businesses to enjoy a more engaged and committed workforce. In a remarkable example, a company in Iowa that incorporated daylighting into their workplace design experienced a staggering 200 percent decrease in turnover rates and tripled their pool of job applicants.
Beyond the tangible benefits, such as increased productivity and reduced absenteeism, employees in spaces with natural light and views of nature generally tend to focus 15 percent more on primary tasks. This heightened level of concentration and engagement positively impacts overall job satisfaction and well-being. With 39 additional work hours per year in productivity per employee, the value of well-designed workspaces becomes evident as an investment in both the employees' mental health and the company's bottom line.
The financial implications are also important. For every $1 spent on building energy costs, there is approximately $10 spent on the building space (rent or ownership) and $100 spent on productivity costs including employee salaries, benefits, and absenteeism. Therefore, any design decision that harms the indoor environmental quality (IEQ), functionality, or occupant health by even a small fraction of a percent will offset any small energy savings by much larger negative impacts and increased costs in the full use of the building.
Steve Selkowitz, principal of Stephen Selkowitz Consultants and affiliate at Lawrence Berkeley National Laboratory, also addressed the ongoing hurdles to the adoption of such high-performance solutions—particularly the greater cost. “We need to convince owners to make investments in things they aren’t doing right now,” Selkowitz said. “Most owners are going to care a little bit about the planet. But they care more about the people that occupy the space. So, we need to bring it back to the occupants.”
Photo: Benjamin Benschneider; courtesy of Sentech Architectural Systems
It is important that designers consider the positive impact of daylighting and views on mental health while also integrating energy efficiency and thermal comfort elements.
Glazing Design for Daylighting, Biophilia, and Privacy
Architects are charged with satisfying many different design goals simultaneously, especially with new challenges such as net-zero energy goals.
“I worry that there is a misunderstanding of the balance between energy efficiency and window area, which is related to daylighting and views,” says Dr. Thomas Culp, owner of Birch Point Consulting, and co-vice chair of the ASHRAE 90.1 standards committee, among other committees. “If we are not careful, this will lead to something I am calling ‘new-age brutalism,’ buildings that look good on paper in a simplistic energy model with small openings but that are actually poorly designed spaces with restricted views. I try to personalize it when talking to architects. Would you want your child trying to learn in a classroom with no natural daylight? Or your mother recovering in a patient room with no window? We need healthy spaces to live, work, learn, play, and heal, and natural daylight and views are essential to that. Buildings serve a purpose for people, businesses, and industry. They will use energy; we just need to do it efficiently and cleanly. It’s all about balance.”
It is important that designers consider studies that demonstrate the positive impact of daylighting and views on mental health. Understanding the latest technologies, product options, and design strategies can also ensure architects are creating spaces that support the mental health of occupants.
“There are very good tools for daylighting analysis out there now to assess the floor coverage, control layout, and energy savings,” says Dr. Culp. “But that is only half of the puzzle. Studies show the health and wellness benefits are tied to both natural daylight and quality views. Design teams should also be careful to look at view angles based on the use of the space. For example, some people say glazing low to the floor in a midrise or highrise building is not useful, but that’s not true. There are important view angles both horizontally and vertically, looking both to the sky and down to the surrounding area. And of course, use the highest performance systems. Don’t just use what you did on the last project; look at the new technology in both glazing and framing systems, such as fourth surface low-e, triple glazing, vacuum glazing, advanced higher performance thermal breaks, building integrated photovoltaics, etc.”
Window Type Selection
Architects can specify various window types that are specifically designed to optimize daylight penetration while simultaneously controlling glare and heat gain. These specialized window glazing technologies play a crucial role in achieving effective daylighting, creating a well-lit and comfortable interior environment for building occupants.
Low-E Coatings: Low-emissivity (low-e) coatings are thin, transparent layers applied to the surface of the glass. These coatings are designed to minimize heat transfer through the window, thereby reducing both heat gain during hot weather and heat loss during cold weather. Low-e coatings work by reflecting a significant portion of the infrared radiation (heat), while still allowing visible light to pass through. This helps maintain a more stable indoor temperature and decreases the reliance on heating and cooling systems, contributing to energy efficiency.
Spectrally Selective Coatings: Spectrally selective coatings are another type of advanced glazing technology that provides greater control over the solar energy entering the building. These coatings are engineered to selectively block certain wavelengths of light, including infrared and ultraviolet radiation, while allowing visible light to pass through. By filtering out the unwanted portions of the solar spectrum, spectrally selective coatings can significantly reduce heat gain while maintaining good daylight levels. This helps maintain a comfortable indoor environment while reducing the demand for air conditioning.
Tinted Glass: Tinted glass is a type of glazing that contains additives to alter the color and light transmission properties of the glass. Tints can range from light to dark, and they help regulate the amount of sunlight and heat entering the space. Tinted glass is often used in regions with intense sunlight exposure to control glare and reduce solar heat gain, especially in buildings with large south or west-facing facades.
Double and Triple Glazing: Double and triple glazing refers to windows with two or three layers of glass separated by air- or gas-filled spaces. These multiple layers provide enhanced insulation and reduce heat transfer, improving the overall energy efficiency of the building. The extra layers of glass can also help reduce noise transmission from the outside, especially if laminated glazing is incorporated, creating a quieter and more comfortable indoor environment, which can positively affect occupant mental health.
Dynamic “Switchable” Glazing: Dynamic glazing, also known as smart or switchable glazing, is an innovative technology that can adapt its transparency in response to external factors like sunlight intensity or electric current. Electrochromic and thermochromic glazing are examples of dynamic glazing. By dynamically adjusting the glazing's opacity, these windows can control the amount of daylight and solar heat entering the building, providing a highly customizable and responsive daylighting solution.
Photo: Benjamin Benschneider; courtesy of Sentech Architectural Systems
Architects who carefully consider the orientation and location of windows can create spaces that are well-lit, comfortable, visually engaging, and support positive mental health.
Window Placement
Strategic placement of windows is a fundamental aspect of architectural design that allows architects to harness natural light effectively and provide occupants with desirable views of the surrounding environment. Architects who carefully consider the orientation and location of windows can create spaces that are well-lit, comfortable, visually engaging, and also support positive mental health.
According to Lisa Heschong, “The placement of a window... determines not only the flow of daylight into a building but also the view out of a building. Not many other architectural elements have such distinctly dualistic, and sometimes contradictory, purposes. Where we might want the most daylight illumination in a room may be quite different from where we want to look out. Composing a symphony of daylight illumination inside a building could potentially be at odds with which perspective we desire of the outside world. Resolving this discrepancy is certainly one of the challenges of artful daylighting design.”
South-facing windows receive the most direct sunlight throughout the day, making them an ideal placement for optimizing daylighting. By incorporating larger windows on the southern facade, architects can capture abundant natural light, especially during the winter months when the sun's angle is lower. This not only illuminates the interior space but also contributes to passive solar heating, reducing the reliance on heating systems and enhancing energy efficiency.
Windows on the east and west sides can provide beautiful morning and evening views, but they are also more prone to excessive solar heat gain, especially during hot seasons. To mitigate this, architects may incorporate shading devices, such as overhangs, louvers, fins, or awnings, to block or diffuse direct sunlight when it's most intense. This helps maintain a comfortable indoor temperature and reduces the need for air conditioning.
North-facing windows provide a more consistent, indirect light throughout the day since they receive less direct sunlight. Although they may not offer as much natural light as south-facing windows, they can still be strategically placed to supplement daylighting without causing glare or overheating. North-facing windows are particularly suitable for areas where a more diffused and evenly distributed light is desirable, such as art studios or office spaces.
The use of daylight modeling tools during the design phase can help architects simulate the effects of natural light at different times of the day and year. This approach allows them to optimize glazing design for both natural light availability and visual comfort, creating spaces that are well-lit and pleasant to inhabit.
Skylights and Clerestory Windows
In addition to traditional windows, architects can incorporate skylights and clerestory windows to introduce natural light from above. Skylights placed on the roof bring in sunlight directly from overhead, illuminating the space below and creating a sense of openness. Clerestory windows, positioned at the upper part of a wall, allow daylight to penetrate deeper into the interior without compromising privacy.
According to one study, 49 retail chains in California that were retrofitted with skylights experienced a 40 percent increase in sales after the addition of skylights. Further research by Terrapin Bright Green indicates that, on average, skylights contribute to a statistical increase of $1.55 per square foot in sales for grocery stores, clothing outlets, and retail chains nationwide.
What makes skylights such an effective source of daylight is their ability to bring in light from the brightest part of the sky, reaching areas untouched by perimeter windows. Not only do they direct sunlight straight into spaces, but they also capture light reflected from clouds and various surfaces, creating a dynamic and pleasant illumination.
Biophilic Design and Ventilation
The concept of daylighting and view is part of “biophilic design” in which architects connect people with nature by incorporating natural elements, patterns, and processes into the built environment. This design philosophy recognizes the innate human need for contact with nature and acknowledges the positive impact that nature has on our well-being. Integrating biophilic elements into architectural glazing can have profound effects on occupants' mental health and overall sense of well-being. Maximizing daylight in all the ways discussed above is also part of biophilic design because the distribution of natural light creates a biophilic environment.
The strategic placement of windows enables architects to frame and capture captivating views of the surrounding landscape. By situating windows to align with specific focal points or key features outside, such as a scenic vista, a lush garden, or an architectural landmark, architects can enhance the overall experience of being inside the building. Views of nature and aesthetically pleasing environments have been linked to reduced stress levels. Even urban views with significant sky exposure can evoke feelings of connection to nature, reduce stress, and enhance the overall ambiance of the space.
Incorporating living walls or vertical gardens adjacent to glazing can bring nature directly into the indoor environment. These green installations also can improve air quality and create a calming and visually appealing setting, fostering a sense of tranquility and connection to nature. And, biophilic design can be achieved through the glass itself, such as through decorative glass and dynamic glazing. Decorative glass with patterns resembling natural elements like leaves or flowing water can create a more organic and inviting atmosphere. Dynamic glazing, which adjusts its transparency based on factors such as sunlight intensity, can make occupants feel connected to the changing natural environment.
A multitude of studies have demonstrated the positive impact of biophilic design on mental health and well-being, all of which go hand-in-hand with the studies on natural light and views. The evidence supporting the positive effects of biophilic design on reducing stress, improving cognitive function, enhancing mood, and overall mental restoration highlights the importance of integrating nature-inspired elements in our built environments for a healthier and happier living and working experience.
In addition, large operable glass windows and doors provide a literal connection to the outdoors—encouraging building occupants to step outside and utilize outdoor areas for serene relaxation, dining, entertaining guests, and other activities.
Natural ventilation from operable windows can have several positive effects on occupant health and well-being. It can help improve indoor air quality by bringing in fresh air from the outdoors and flushing out stale indoor air. This can reduce levels of indoor air pollutants, such as volatile organic compounds (VOCs) and carbon dioxide, which can cause respiratory problems and other health issues. It can help regulate indoor temperature and humidity levels, creating a more comfortable indoor environment, and ultimately leading to a reduction in the need for mechanical cooling and heating, which can save energy and reduce costs.
The regulation of indoor temperature and air quality leads to another benefit: it can promote better sleep quality. Studies have shown that, just like with natural light, exposure to fresh air and lower indoor temperatures can lead to deeper, more restful sleep. During the day, natural airflow can promote relaxation and reduce feelings of anxiety and stress, which tends to have a ripple effect of mental health benefits for occupants.
Designing for Security
To support occupant mental health, architects must strike a balance between safety, security, and comfort. This involves integrating protective glazing solutions seamlessly into the overall design, considering the specific needs of the occupants, and promoting an environment that fosters positive mental well-being. By using glazing strategically and combining it with other design elements that promote natural light, views, and a sense of openness, architects can design a space that is both secure and supportive of occupant mental health.
School Security Glazing
In response to increasing concerns about school safety, architects may incorporate forced entry-resistant glazing in areas like entryways and administrative offices. The goal is to create a secure environment that reduces the potential for harm by intruders and provides more time and visibility for first responders. Still, to support occupant mental health, these glazing solutions should be designed in a way that does not make students and staff feel excessively confined or anxious. Integrating elements like natural light, views of outdoor spaces, and calming aesthetics can help maintain a positive learning atmosphere.
Hurricane-Impact Glazing
Hurricane-impact glazing is designed to protect buildings from high winds, flying debris, and water intrusion during severe weather events. While this type of glazing provides essential safety benefits, architects should ensure that it allows for ample daylighting and views during non-hazardous periods. Maximizing natural light, especially in educational settings, has been shown to positively impact cognitive function and the overall learning experience.
Fire-Rated Glazing
Fire-rated glazing is used to contain the spread of fire and smoke while allowing for visibility during emergencies. In schools and other occupied buildings, it's essential to balance fire safety with the occupants' mental well-being. Architects can strategically incorporate fire-rated glazing in corridors and exit areas to maintain visual connections, reduce feelings of panic, and aid in wayfinding during an evacuation.
“The number of options and plethora of technical data can sometimes be overwhelming,” says Julia Schimmelpenningh of Eastman Chemical Company, who spends her days testing—and often breaking—glass so that it will hold up against car accidents, hurricanes, active shooter attacks and daily exposure to harmful UV rays. “Understanding what performance is needed and what they want out of the glass is the key to getting the correct specification. The other challenge is oftentimes connecting with the proper supplier, as the local glass shop may not necessarily have what you need readily available. So planning, research, and utilization of technical services and associations that are experts in glass can help.”
Designing for Privacy
One of the primary considerations for architects is ensuring the privacy of building occupants. While large windows and expansive glazing can offer stunning views and flood interiors with daylight, they can also compromise the sense of privacy for those inside. The feeling of being constantly exposed to the outside world can cause discomfort, stress, and a lack of security in private spaces like bedrooms, bathrooms, and areas meant for personal reflection.
To address these concerns, architects can strategically position windows and glazing elements to avoid direct lines of sight into these private areas. By carefully selecting the placement and size of windows, occupants can still benefit from natural light and views without feeling exposed or intruded upon by external observers. Public and communal areas can have more expansive glazing and views to promote a sense of openness and connection, while private and sensitive areas should be carefully secluded and shielded from external views.
Another effective solution is the use of frosted or patterned glass. This type of glass is particularly useful for spaces like bathrooms or conference rooms, where privacy is crucial. Patterned glass incorporates artistic designs or textures that break up the view, providing a similar level of privacy while adding an aesthetic touch to the space.
Switchable private glass, also known as smart glass or privacy glass, is an innovative type of glazing that can change its transparency from opaque to transparent or vice versa with the application of an electric current. This unique characteristic allows it to provide on-demand privacy and control over the amount of light entering a space without the need for traditional window coverings like curtains or blinds.
The primary principle behind switchable private glass is the use of special materials, such as liquid crystals or suspended particle devices (SPDs), that can alter their molecular alignment when an electric current is applied. When the glass is switched "on" or transparent state, the molecules align, allowing light to pass through and creating a clear view. When the glass is switched "off" or opaque state, the molecules disperse, scattering the light and making the glass appear frosted or obscure, thereby obstructing the view and ensuring privacy.
STANDARDS AND PERFORMANCE
Glazing designs focused on natural light and views can optimize both mental and physical needs, whether at home, school, work, hospitals, transportation centers, or even vehicles. And larger glass sizes are being used in both residential and commercial design to increase that ability to enhance natural daylight and view. It is important to note that some positive benefits of natural light and views go out the window, so to speak, if other elements, like thermal discomfort and glare, are not considered carefully. This is one of many reasons it is important for architects and other specifiers to understand the misconceptions and realities of glazing and approach it as a whole system. Achieving the goals of daylighting and views need to be understood within the context of performance standards, which are valuable to occupants and affect physical and mental health as well.
According to a recent National Association of Homebuilders study, of all the efficient features one could have, 83 percent of homeowners found it essential or highly desirable to have energy-efficient windows, making it number one on the list of priorities.
When selecting window assemblies for big-glass designs, there are multiple factors to consider. For instance, while increasing the amount of glazing can increase heating and cooling demand, the daylighting achieved through more glazing can significantly reduce electric lighting demand. Reducing the amount of heat transfer between the interior and exterior of a building is one way to reduce heating and cooling costs and improve occupant comfort. The ability to control solar heat gain is also important. While some solar heat gain may be desirable in colder climates, where it can help reduce heating costs, excessive solar heat gain can be a problem in warmer climates, where it can increase cooling costs and make indoor spaces uncomfortable. High-performance glass and the use of thermal barriers can also be used to help boost energy efficiency and control solar heat gain.
Energy-efficient windows are typically designed to reduce both heat loss and solar heat gain, and may include features such as low-emissivity coatings, reflective coatings, thermal barriers, and insulating gas fills between panes of glass. By selecting windows that address both issues, architects can help reduce energy costs for occupants and improve the comfort of indoor spaces.
Low-emissivity (low-e) coatings are designed to reduce the amount of heat that escapes through the glass in cold weather. Emissivity is a measure of how well the surface of an object absorbs and re-radiates (or gives off) thermal energy. Very reflective surfaces have a low emissivity, and duller objects that absorb heat have a high emissivity. Emissivity is measured on a scale ranging from 0.0 to 1.0, with 0.0 being a perfect reflector and 1.0 being a perfect emitter, aka a “blackbody.” (A blackbody is a theoretical object in physics that does not really exist but is a useful concept when talking about emissivity.)
Low-e coatings work by reflecting heat back into the room, rather than allowing it to escape through the glass. In addition to reducing heat loss in winter, certain solar selective low-e coatings can also help control solar heat gain in the summer by reflecting some of the sun's heat back outside. The microscopically thin, transparent metal or metallic oxide layers deposited on a glass surface can be selected from a variety of options with different levels of heat gain control to match different climate needs.
Case Study: Family Service & Guidance Center in Topeka, Kansas
Photo courtesy of Architect One, Inc.
Interior of the new Center shows a second-floor suite featuring clearstory glazing and natural light.
Project Overview: Family Service & Guidance Center leads the way in children's mental health services, serving over 10,000 children, teens, and families from more than 30 Kansas counties annually. Recognizing the limitations of their current space to meet the growing demand, Architect One, Inc., led by Scott Gales, Jacquelyn Rakoski-Diediker, and Andrew D. Thomas, took up the challenge of designing a new facility that would cater to their client’s needs while promoting mental well-being.
Impact of Natural Light: Freed recognized the significance of natural light for mental health and well-being. Previous experiences with artificial lighting revealed its negative effects on clients dealing with mental health issues. With the new design, the facility's lighting closely mimics natural light, harnessing the benefits of Vitamin D and serotonin, which help reduce anxiety and improve mood and sleep.
Site Selection for Views: Adopting a holistic approach, the architects thoroughly analyzed potential sites and building requirements. Keeping in mind the unique needs of the clients, they focused on functions that support mental health and addressed security concerns. Ultimately, they chose the existing South Parking Lot, providing picturesque views of a large pond and surrounding trees, creating a serene environment away from busy streets.
Privacy and Daylighting: “We are with clients who are suicidal, maybe homicidal, and windows are just a huge risk factor,” says Travis Freed, LMLP, Director, Crisis & Recovery Services. “That’s a complication of it, right? You have to have secure, impact-resistant windows, and a lot of times you'll see facilities put bars on windows. You'll see facilities put opaque covers over the entire windows, so it really reduces the amount of natural light coming in. In our current facility, we have large windows in our bedrooms, but we basically put plexiglass in them, which works from a safety standpoint, but it wasn't ideal for light coming in.”
For the new facility, the architects utilized advanced modeling techniques to optimize the building's orientation to harness natural light. The goal was to create an atmosphere akin to outdoor lighting, positively impacting mood and well-being. To ensure privacy for the children without compromising on natural light, the architects used a combination of glazing techniques. Frosted films on the lower halves of windows allowed ample daylight while maintaining discretion from inside and outside. The upper portions of the windows were fitted with clear laminated glass to enhance brightness and light transmission.
Color and Material Selection: The architects aimed to instill a warm and inviting ambiance within the center. After extensive tests with around 20 different colors, they settled on a soothing beige finish and a calming blue finish for the interior walls. To ensure safety, impact-resistant drywall was used throughout the bedrooms, providing a secure environment for the children.
Creating a Sense of Warmth: Emphasizing the importance of a welcoming atmosphere in the bedrooms, the architects incorporated natural light through clear glazing and complemented it with natural wallcoverings. This design approach aimed to establish a connection to nature, known to facilitate the healing process.
Client Involvement and Collaboration: Throughout the project, the architects collaborated closely with the Family Service & Guidance Center staff, who played a vital role in shaping the program and design elements to cater to the specific needs of the children and adolescents. The architects diligently worked to bring the staff's vision to life, showcasing the power of collaboration in creating spaces that positively impact the lives of those in need.
Glare Control Standards
When it comes to architectural glazing, glare control is an essential aspect to ensure occupant comfort, productivity, and safety. Glare can be caused by excessive brightness or contrast in the visual field, leading to discomfort, eyestrain, and reduced visibility. Various standards and guidelines exist to address glare control in architectural glazing.
International WELL Building Institute (IWBI) WELL Building Standard: This performance-based system for measuring, certifying, and monitoring features of the built environment that impact human health and well-being includes criteria for glare control to create comfortable and productive spaces.
LEED (Leadership in Energy and Environmental Design) Rating Systems includes prerequisites and credits that address glare control as part of the overall sustainable building design.
American National Standards Institute (ANSI) and Illuminating Engineering Society (IES) joint publication RP-1, "Recommended Practice for Daylighting Buildings," offers guidance on the design and use of daylight in buildings, including strategies for glare control.
These standards and guidelines often recommend specific glazing properties, such as visible light transmittance (VLT), shading coefficients, and solar heat gain coefficients, which can help control glare while still allowing sufficient natural light into the building.
Thermal Comfort Standards
Thermal comfort standards for architectural glazing are essential to ensure that the glazing systems used in buildings provide a comfortable indoor environment for occupants, taking into account factors such as temperature, humidity, air movement, and radiant heat.
ASHRAE 55 is one of the most widely recognized standards for thermal comfort in buildings. It provides both thermal comfort criteria and methods for calculating indoor thermal environmental conditions. The standard specifies acceptable temperature ranges and other factors like air speed, humidity, and clothing insulation for various types of spaces.
ISO 7730 is similar to ASHRAE 55 and provides guidance on the determination of thermal comfort requirements for different types of occupants and activities. It takes into account factors like air temperature, mean radiant temperature, air speed, humidity, and clothing insulation to assess thermal comfort conditions.
LEED includes prerequisites and credits that address thermal comfort in buildings, and this can indirectly influence glazing design decisions. The LEED credit for thermal comfort also references the ASHRAE 55 standard.
These standards and guidelines often specify acceptable temperature ranges, thermal transmittance (U-value), solar heat gain coefficient (SHGC), shading coefficients, and glazing properties to ensure the glazing systems contribute positively to thermal comfort. Proper glazing selection, orientation, and the use of shading devices can significantly impact the indoor thermal environment and occupants' comfort levels. It's crucial for architects and designers to consider these standards when integrating glazing systems into building design to achieve optimal thermal comfort for the occupants.
Security Standards
The new ASTM F3561 standard was recently assembled by members of the National Glass Association in coordination with ASTM International for specifiers looking to utilize the latest in glazing security solutions for schools and other buildings facing active shooter threats. The increase of school shootings in both frequency and severity in recent years led NGA to recognize the need for a relevant, accurate international standard to protect entrance to facilities from intruders through locked fenestration in response to this increase. The NGA assembled a School Security task group charged with reviewing the current referenceable standards for school security testing. They identified several gaps in the testing standards including repeatable, mode-driven, and consensus-based fenestration test methods. These gaps included tests for system-weakening and forced entry assaults.
The new consensus-based standard, “ASTM F3561 Standard Test Method for Forced-Entry-Resistance of Fenestration Systems After Simulated Active Shooter Attack,” was officially announced in July 2022. Created through ASTM International F12 Security Systems and Equipment Committee, the new standard underwent a thorough review by ASTM International and was approved for publication on August 1, 2022. It now serves as the benchmark testing standard for forced entry-resistant doors and windows.
SOURCES
“What Florence Nightingale Can Teach Us about Architecture and Health”.
“The Economics of Biophilia: Why Designing with Nature in Mind Makes Financial Sense”: Terrapin Bright Green LLC, 2012.
“Visual Delight in Architecture", by Lisa Heschong available through Routledge.
“LISA HESCHONG SHARES DATA ABOUT DAYLIGHTING AND WINDOW VIEWS".
Erika Fredrickson is a writer/editor focusing on technology, environment, and history. She frequently contributes to continuing education courses and publications through Confluence Communications. www.confluencec.com
